FIGURE 1.

(A) Radioligand binding studies in membrane fraction of A_2A-AR-overexpressing animals. The experiments were performed as described in Section “Materials and Methods.” The binding of [³H]-labeled A_2A-AR-agonist CGS 21680 could be almost completely blocked by addition of A_2A-AR-antagonist ZM 241385, whereas A₁-AR-antagonist PSB36 and A₃-AR-antagonist MRS 1220 did not affect the binding of [³H]-CGS 21680. No specific binding was detectable in membrane fraction from WT animals. (B) Immunohistological staining of ventricular tissue from A_2A-AR-overexpressing and wild type (WT) animals. A_2A-AR was visualized using a monoclonal antibody against A_2A-AR and goat anti-mouse antibody conjugated to Alexa Fluor 594 (red, upper row). The nuclei were counterstained using DAPI (blue). Note staining of cardiomyocytes from A_2A-AR animals, mainly in the vicinity of the sarcolemma. Lower row: negative controls with omission of the primary antibody. ^⋆p < 0.05 vs. [³H]-CGS 21680 alone.